1992 vx tranny.....

hey guys in the past i've swapped out trannys on my 1992 4dr ex civic which had the D16Z6 in it and my friend said hey use a 92 vx hatchback trans u'll get a little more speed so i did it and my 1st gear topped out at like 40mph and 2nd was about 65mph my 3rd was about 115mph when the govern kicked in and went to 120mph then let off never able to redline 3rd........ if any one could explain how the heck this is possible that would be great thank you..........